The text is:
aaaaaaaaaaaaa
aaaaaaaaaaaaa
aaaaaaaaaaaaa
aaaaaaaaaaaaa
Select single vertical column of a’s. Find/Replace: regex, match case, selection only.
Find: [a-z]
Replace: anything
Nothing is replaced.
Replacement also fails if block selection is 2,3,4 columns wide. It works is block selection is >4 chars wide.
The following replace fails if block selection is 1,2 or 3 columns wide. It works if 4 or more columns selected.
Find: (.*)
Replace: x1